Economic Valuation of Green and Blue Nature in Cities: A Meta-Analysis

There is an increased interest in applying nature-based solutions for addressing various urban challenges, such as those related to air pollution, climate change, and (mental) health. It is clear that nature can bring various benefits to city inhabitants, but the economic value of nature is not always well recognized. In this study we present a meta-analysis of a rapidly expanding literature that applied stated preference valuation methods to value green and blue urban nature in a variety of contexts. We estimate value transfer functions based on primary studies that elicited nature values from in total more than 41,000 respondents worldwide. We obtain insights into the main determinants of values of urban nature, in terms of study and methodological characteristics, types of nature, and ecosystem services. Main findings are that the per hectare value of nature is negatively related to the size of the nature area, and positively related to income and population density. Parks are the most highly valued types of urban nature, and aesthetics and cultural heritage services are the most highly valued ecosystem services it provides. Moreover, certain methodological choices in eliciting nature values appear to affect the final valuation results, such as the payment vehicle in stated preference surveys, and to some degree the valuation method. We present and illustrate the use of benefit transfer functions, which can be used for estimating the value of specific nature types and ecosystem services in a variety of urban settings.